The apparatus and method of the fan-beam resection problem are disclosed in the PCT application No PCT/US2008/067464, Pub. No WO/2009/154625, publication Date-Dec. 23, 2009, international filing date-Jun. 19, 2008 entitled “POSITIONING DEVICE AND METHOD FOR DETECTING A LASER BEAM”, by SCHUMACHER, Lars; (DE) and CONNER, Robert, G.; (US), hereinafter referred to as PCT '464.
The technology disclosed in PCT '464 relates to a positioning device and method for detecting light of fan shaped laser beam, as well as to a positioning system comprising the device and to a light emitting device emitting the fan shaped laser beam, which enable to find a spot of a laser beam easier and quicker. The positioning device comprises a detector for detecting light of a fan shaped laser beam rotating around a propagation axis with a direction of rotation and having two detector elements arranged in a known spatial relation for outputting a detection signal when irradiated; and a position determining unit to obtain a first set of detection signals from the detector elements, determine a first time relation between the detection signals of the first set, and determine a positional relation between the detector and the propagation axis based on the first time relation. PCT '464 is incorporated in the present patent application.
However, the solution offered in PCT '464 assumes that the detectors are arranged in a plane and the axis of the fan-beam laser is perpendicular to the plane. This limits the utility of the idea.